1. Field of the Invention
This invention relates generally to a flushing mechanism for use in toilet flushing applications. More particularly, the invention relates to a low water volume, pressurized water closet reservoir.
2. Description of Related Art
A typical flushing system includes a tank connected to a toilet bowl. The tank holds approximately 14 to 16 liters (4 to 6 gallons) of water and is positioned above the level of the bowl. In such a system, flushing of the bowl is achieved by breaking a seal at the bottom of the tank and releasing water contained within the tank. The weight of the water due to gravity generates a high velocity flow that then carries bowl water and waste into the sewer line. In this type of system, the volume of the water from the tank is used to effect the flushing and replenishing of the bowl, and a minimum of three and a half to four gallons of water are typically required to flush the bowl. Because of heightened concern caused by decreasing water supplies and the consequent need for water conservation measures, it has been legislated that for new construction no more than 1.6 gallons can be used to flush a toilet. Therefore, all new toilets are designed for this requirement whether they be the type described above or pressurized design. Gravity type toilets that are limited to a flush volume of only 1.6 gallons tend to perform poorly, and often require double flushing. Therefore, there is a trend to replace gravity-fed water closets with pressurized water closets. These pressurized water closets typically have a pressurized reservoir to hold the flush water, and a valve which is actuated by the user to discharge the pressurized water into the bowl and thereby carry the waste water into the sewer line.
Several of the currently available low water volume toilet flushing mechanisms rely on the use of a pressurized storage tank that is filled with compressed air in addition to the flushing charge of water in order to increase the head pressure of the reduced volume flushing charge.
U.S. Pat. No. 5,136,732 (Anderson) discloses compression of air that is initially at atmospheric pressure within a storage tank when pressurized water (at mains pressure) enters the storage tank. This compressed air assists in the expulsion of the reduced volume flushing charge of water at a high velocity by expanding rapidly when an aperture in the storage tank is open during the flushing phase of a cycle of operation, thereby allowing flushing charge to flow into the toilet bowl.
U.S. Pat. No. 4,233,698 (Martin) discloses a low water volume toilet flushing mechanism in which air is introduced into and compressed within a main storage tank as the flushing charge of water enters the main storage tank. The pressure of the trapped air within the main storage tank pushes the flushing charge out from the main tank during the discharge phase of a cycle of operation.
U.S. Pat. Nos. 4,984,311 and 5,115,521 (Aramides) both disclose a low water volume toilet flushing mechanism that relies on the contraction of a controlled contractible container such as a bellows or elastic bladder or upon the use of a piston spring system to generate the necessary head pressure in order to achieve a suitable velocity in the flushing charge of water.
U.S. Pat. No. 848,951 (Aeppli-Stocker) discloses a fluid metering and dispensing device that relies upon the force exerted by the pressurized fluid being dispensed for biasing the device to a closed position during cycles of actuation, rather than using springs or other mechanical means.
U.S. Pat. No. 5,526,000 (Basile) discloses a flushing mechanism that uses a reduced amount of water that is contained within an elastic bladder which expands to provide pressure.
U.S. Pat. No. 5,848,441 (Smith) discloses a simplified pressure assist toilet flushing mechanism which incorporates a thin-walled pressure tank.
Although pressurized water closets significantly reduce the amount of water used per flush, closets of this type also suffer from several drawbacks. One problem encountered with a pressurized water closet is that, it tends to be mechanically complicated and prone to breakage or leakage. Another problem is that such systems tend to be noisy. In addition, such systems tend not be retrofittable into existing water closets. They must be installed with a special bowl and tank designed for this system which makes them expensive.
U.S. Pat. No. 5,361,428 granted to Martin for xe2x80x9cHydraulically Controlled Pressurized Water Closet Flushing Systemxe2x80x9d, U.S. Pat. No. 5,970,527 granted to Martin for xe2x80x9cPressurized Water Closet Flushing Systemxe2x80x9d, U.S. Pat. No. 3,817,279 granted to Larson for xe2x80x9cFluid Control Mechanismxe2x80x9d, U.S. Pat. No. 3,817,286 granted to Caron for xe2x80x9cHydraulic Flush Tank with Improved Seating and Resealing Meansxe2x80x9d, U.S. Pat. No. 3,817,489 granted to Caron for xe2x80x9cHydraulic Flush Tank with Improved Seating and Sealing Meansxe2x80x9d, U.S. Pat. No. 3,820,171 granted to Larson for xe2x80x9cFluid Control Mechanismxe2x80x9d, U.S. Pat. No. 3,820,754 granted to Caron for xe2x80x9cHydraulic Flush Tank with Improved Seating and Sealing Meansxe2x80x9d and U.S. Pat. No. 4,233,698 granted to Martin for xe2x80x9cPressure Flush Tank for Toiletsxe2x80x9d, all describe a flushing valve member that is biased downwardly. The flush valve of the present invention is normally biased to the open position and locked in place by a sealing plug. This permits a greatly simplified structure which produces a reliable flushing system.
Thus, there is a need for a pressurized water closet that can be retrofitted into a conventional water closet and that provides a mechanically simple flushing device with reduced or substantially eliminated problems with leakage and breakage that is reliable and quiet and avoids the leakage and breakage problems of the prior art.
The invention reduces the difficulties and disadvantages of the prior art by providing a simple pressurized water closet flushing system for dispensing a metered amount of water into a toilet bowl. The pressurized container can be manufactured using conventional plastic injection die technology for a relatively low cost and is easily adaptable to the conventional water closet.
Accordingly, the present invention provides a pressurized flushing system for discharging liquid into a toilet bowl comprising:
a sealed container for storing a pre-determined volume of the liquid under pressure;
an inlet to the container for connection to a liquid supply source under pressure;
an inlet valve to permit liquid flow through the inlet until the pre-determined volume in the sealed container is reached;
an outlet for discharging liquid under pressure;
an outlet valve movable between an open position to permit liquid discharge through the outlet and a closed position to seal the outlet, the outlet valve being urged by internal pressure within the sealed container toward an open position of the outlet when the pre-determined volume of liquid is in the sealed container; and
an actuator that locks the outlet valve in the closed position against the internal pressure of the container whereby operation of the actuator unlocks the outlet valve to permit movement of the outlet valve to the open position.
The flushing system of the present invention provides a secure and simple means for dispensing a metered amount of water into a toilet bowl, thus reducing excessive water usage. In addition, the device has a novel pressure release mechanism which prevents dangerous pressure build-ups within the reservoir. The device is easily installed into most commercially available toilet systems and can generate relatively high pressures for dispensing water into the toilet bowl, particularly in those areas where water conservation is necessary. The previously described problems of many prior art devices are thus reduced considerably or essentially eliminated. In addition, there is another embodiment of the device which can be used as a standalone device without the need for insertion into a water closet reservoir.